1. Field of the Invention
The present invention relates to a metal complex compound and an organic electroluminescence device containing the compound.
2. Description of the Related Art
Since organic electroluminescence devices (organic EL devices) can provide light emission having high luminance even at a low driving voltage, active research and development on them have been made in recent years. In general, organic EL devices have organic layers including a light emitting layer and a pair of electrodes sandwiching these layers therebetween. Electrons injected from a cathode and holes injected from an anode recombine in the light emitting layer and energy of excitons thus generated is utilized for light emission.
Use of a phosphorescent material has recently accelerated improvement in the efficiency of the device. Iridium complexes and platinum complexes are known as the phosphorescent material (refer to, for example, U.S. Pat. No. 6,303,238 and International Patent Publication No. 00/57676), but development of devices satisfying both high efficiency and high durability has not yet led to success. There is therefore an eager demand for the development of a phosphorescent material capable of satisfying both of them.
There are disclosed organic electroluminescence devices containing, in a light emitting layer thereof, a material of a phenylpyrazole tetradentate platinum complex (for example, JP-A-2006-232784 and JP-A-2007-96255). These devices are however insufficient from the viewpoint of luminescence quantum efficiency, driving voltage, consumption power, and durability and are required to be improved further by specifying the structure of the platinum complex. In particular, they are required to have improved luminescence quantum efficiency, driving voltage, consumption power, and durability in phosphorescence emission of a blue to bluish green light which is a shorter wavelength light.